The present invention relates to a chair, and in particular to a chair for enhancing a waist strength, which can be easily used by anybody for thereby exercising waist, pelvis and belly muscles.
Generally, a chair is designed so that a user can easily sit. The chair may be classified into many types based on their types, uses, structures and materials as an industrial society advances.
First, in the types of chairs, they may be classified into a stool, a chair, an arm-resting chair, a long chair, a lying down chair, a locking chair, etc.
Here, various cultures come into and are developed, people, who are used to just sit and enjoy their lives, increase more. The people, who are not used to sit on the chair, spend at least hours on the chair.
FIG. 1 is a perspective view illustrating a conventional chair. The conventional chair comprises a backrest 10, a seat 20 connected with the backrest 10, a cylindrical connection unit 40 which is installed at a rear center portion of the seat 20 for adjusting the height of the seat 20 depending on an operation of an up and down adjusting lever 30, and legs 50 which support the connection unit 40.
However, in the above conventional chair, when a user works for a long time, sitting on a chair for a long time. Since the chair does not move forward, backward and up and down directions, the user may gain weight in his waist and belly.
So, the user may gain weight in his belly, so that waist and belly muscles may be weakened for thereby causing a disk disease or a waist disease.